Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

(Sorry in advance for a long post)

I think I implemented the relay mod correctly, but I still get the "service ride control" message. "94 SDV", the earlier poster who reported the same, if you figured it out could you post what you did. Otherwise, if someone could give any advice, it would be appreciated. Here is what I have done:

Following the instructions, I tapped into the wiring for switched power and ground. I connected the gnd line to pin 30 of the relay and the power line to pin 85 of the relay and verified with a volt-ohm meter that the ground line was indeed a ground and that the voltage line contained switched voltage.

Following the instructions, I cut the red wire (C15) going to the module and connected the module side to pin 86 of the relay and the wiring side to pin 87A of the relay. I checked the behavior of these signals with the meter. The module side of the red wire, now attached to pin 86 of the relay, gets pulled to ground by the module about 6 seconds after i turn the key to the on position. My understanding is that this is the module sending the signal that becomes "service ride control". When this occurs the wiring side of the red wire, now attached to pin 87A of the relay, changes from ground to about +8.7 volts. I am assuming this is resulting from the relay getting energized and causing an open circuit between 87A and 30 (ground).

This behavior is basically what I expected from the description of the circuit mod. I thought that possibly 8.7 volts was not enough for the fault logic circuits (i didn't really believe this, but was clutching at straws) , so I tried, as a test, putting a 500 ohm pull-up resistor between the relay pin 87A (wiring side of red wire) and relay pin 85 (+12). With that test in place the voltage on wiring side of the red wire after the relay is energized is about 10.2volts instead of 8.7, but I still got the "service ride control message".

The following is the behavior of the fault codes with four conditions (1) wiring mod, (2) original wiring, (3) open circuit for C15, (4) Wiring harness side of C15 grounded.

Starting with the modification installed, the car stationary and all codes cleared, I switch on the key. After about 6 seconds the “Apply Brake to Shift” message comes up and then the "Service Ride Control" message comes on. Next I display the codes and there is only I039 Current. If I clear the code, then I039 does not come back.

Same test, but this time with the wiring restored to the "pre-modification" state and the behavior (messages and codes) is identical.

The next test was leaving the red wire (C15) cut between the module and the wiring harness. The behavior is almost identical. The only difference is the order of the messages – the “Service Ride Control” comes on before the “Apply Brake to Shift” rather than after.

And lastly, grounding the wiring harness side of C15 circuit. With this wiring there were no codes at startup, hoping that this was the solution I was looking for, I drove the car around, and after about 1 block the “Service Ride Control” message came on and checking the codes, this was indeed I039.

Not knowing precisely how the fault detection works, I do not know how to proceed. I am guessing that the mod is working as it is supposed to and something else is causing the I039 message. Is this crazy talk?

I have seen in this thread that there is a flashing light code that can be checked from the model. The exact text in the thread is “You get into the SSS/CCR system by grounding pin 'C' on the ALDL. On the module there is a white plastic window with a LED behind it. It will flash codes after pin 'C' is grounded. It will repeat the codes as long as it is grounded.” So my question is: what is an “ALDL”, where is it, is the “pin C” on the mysterious ALDL and is, the ALDL just the module back I the trunk which I have been hacking at or is it something else?

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

The ALDL is the grey connector under the dash on the driver's side about 3" to the right of the parking brake. The pins are marked but the markings are hard to see.
You noted cutting a red wire going into the module. On mine I cut the pink wire coming out of the module. Do you have a RED wire coming out of the module? If you have RED going in and RED coming out, could you have cut the wrong wire?
For power I spliced into the solid brown wire. I ran pin 30 to a ground.
I know the instructions call for RED but seemingly that becomes PINK on the output side of the module on my Eldo. I know little of things electrical but I posted what worked for me. I forget where I got that red/pink transition info, but it was from someone on another board who had a handle on the issue.

"SERVICE RIDE CONTROL" message fix

Hi guys,

I think I have a fix for ‘SERVICE RIDE CONTROL / 84’ error message for at least ‘93-’97 STS / ETC with Northstar engine. (I did it on my ’93 STS, but it should be the same or similar for the other years).

There are two main causes for this message – active strut failure and accelerometer failure.

As it’s stated in the shop manual, the resistance of the electric part of the strut should be between 1.5 and 3 Ohm. As it turned out, a resistor within the specified range may successfully simulate this electric load.

I didn’t go into a deep evaluation of this thing but potentially, the current through this load may be high and produce quite an amount of heat (although I didn’t see it getting hot during few weeks of operation). So, as a precaution I would recommend to use resistors for dissipation of 5 or 10 watt. I’ve used two 2W resistors (5.1 Ohm) connected in parallel (for each ‘simulated’ strut). Obviously, the wires going to the strut must be disconnected.

All the resistors have to be connected on one end to CKT 1112 (power). The most convenient (but not that easy to identify) place is the harness in the front of the trunk which makes a loop right in the middle going from the bottom of the rear back seat to the trunk floor.

The wire you’ll be looking for is a thick white one. For its positive identification I strongly recommend to ring it through to the relay. It’s relay ‘F’ in the relay block under the hood (you’ll have to remove the protective cover around the fuse block – under the hood) and it’s the rear one, in the row closest to the fender. Remove the relay and ring through the wire to the trunk.

Once you have the feed from CKT 1112 (in the trunk) you have to identify the wires for the appropriate strut(s) on the 8-pin connector (C3) of RSS module. For RF – D; LF – E; RR - C; LR – E (see the drawing). Cut the wires for the struts to be ‘unsupervised’ and connect each one through its own resistor to the feed (CKT 1112).

Isolate the wires and attach the resistors in a suitable place – remember, they MAY produce a lot of heat…

The second cause may be the accelerometer’s fault. Fortunately, they also can be simulated by the resistors. As it’s said in the description of error codes S070-S073, which are relevant to the problem, the codes and the error message are set if the voltage from an accelerometer is out of 0.5 – 4.5Vrange for more than 0.5 sec. As I’ve figured out, this should be the voltage between ‘+’ and ‘-‘ signal wires of the accelerometer (not the voltage from ‘-‘ or ‘+’to the ground).

As a result, I’ve got a three-resistor divider, which has 100 Ohm resistor from the ground to the ‘-‘ signal wire (as it is in the real accelerometer), 63 Ohm resistor from ‘-‘ signal wire to ‘+’ signal wire and 470 Ohm resistor from ‘+’ signal wire to +8Vsource for the corresponding strut (see the drawing). I believe 5-10% deviation from these values should be ok. (The actual accelerometers, obviously, should be disconnected).

Here the current is minimal so you can use 'regular throughhole’ resistors 0.25 or 0.125W and it may be a very good idea to install them on a piece of a blind board.

The parts you can order at digikey website (with delivery to your place for a reasonable price).

So, if have any comments or would be so exited that you’d want to send me a couple of bucks for beer for going through the hassle of posting this info just contact me at caddybear at live dot com.

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

austiinDeville:

I have a 1994 sedan deville. Intalled the relay to eliminate the SRC message - got same result you did. However, I did get it to work last night, temporarily. Made several runs around block, and SRC message never came up. However this morning when wife drove to church, the SRC msg reappeared along with I039 code (quits when you push the INFORMATION button until restart the car). So I don't know what's going on here.

Today I lifted and grounded the IPC lead at module and msg went away. It came back on when I exceeded 15MPH. Found in manual that the I039 code is generated if the C15 signal is LO greater than 15 mph, and if C15 is HI less than 5 mph. Hooked system back up original (my problem was intermittent and it works OK sometimes for a while). Then noted that C15 was LO (0 volts). Got in trunk with flashlight, had wife drive around block, and observed that C15 went HI at 10mph and over, and dropped back LO when speed went below 10mph. So in this case, I can't see how the relay mod could ever work for me, since with the relay the IPC lead is HI after turning the switch on.

I am a retired electrical engineer, and have extensive background in electronics, so I am considering building a logic circuit that picks up the speed info to the module, and use that circuit to operate a relay that will cause the IPC lead to go from GRND to HI at >= 10mph, and drop back out to GND at <=10mph.

However, I wonder how you solved this problem, if you were able to. The codes in my case indicated a bad LF strut. The struts wiring is still connected. I wonder if that has anything to do with it, since most of the mods posted seem to be related to changing to passive struts in which case the strut wiring is disconnected???

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

i have the deville concours (94) with the 4.6L, but it has the rss system for the ride control. looked at the tsb none of the wires match plus it has three connectors not one like the sss system. codes so60,61,63,72. woukld like to bypass but can not find right bypass diagram. could anyone help
thanks
jon

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

Use the sticky thread at the top of the main Seville/Eldorado Forum titled "How to pull codes" from your car's built-in code reader/scanner system. When you get the codes, if any, write them down, noting whether each is Current or History (C or H); return to the sticky and use the proper link for your year group to open pages with code definitions. You'll be looking for B codes which refer to the ELC (Electronic Level Control) or ALC (Automatic Level Control).

Chances are that the compressor or a component of the compressor system is faulty, the air lines to the shocks have failed, or the shock boots have failed.

Your car does not have air suspension. It uses springs and electric front struts; springs and electric rear shocks in the RSS (Road Sensing Suspension) system. The rear level control compensates for loads in the back seat or trunk.

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

Hello everyone - I hope there are still users here. I too have the Service Ride message on my 94 Sedan Deville dash. Looking in the trunk, at some point in time, a previous owner added the relay to bypass the dash error, but for whatever reason, the wires were reconnected as factory.

I have been searching for the past week for a simple how to troubleshoot the front struts. Right now, they do not do anything. When driving, it feels as if there are no struts on the front end at all, and when i get to 43 mph, the front end starts shaking a lot. it does smooth back out at 54 mph.

I bought this car as a personal challenge - just to have something to do. But, I am totally lost when it comes to the SSS.

If anyone could tell me the exact locations of all of the fuses, relays, and sensors for the front struts, I would be forever indebted to you.

So far, I have checked all of my fuses under the hood and in the trunk and they are all great - will probably just buy all new ones anyways just to be on the safe side.

On the drivers side - behind the rear seat - there are 2 clusters of relays - the one on the left with 6 relays nad the one on the right with only 5 relays. Since, when the rear compressor comes on, I hear the relay click in one of these two clusters, I am guessing that the relays for the front struts are in there somewhere as well. Does anyone know which one it would be for the front struts.

Also, I just checked the 3 wires going to the top of my front left strut - the red wire has a lil over 8 volts dc, and the green/white stripe wire has a lil over 1 volt dc (this is with key in on position, but engine not running). Is this correct?

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

Hi.........There are plenty of older Deville users in CF, but I doubt you'll get much action here in a "sticky". They're really for research info as opposed to questions. You might ask a Moderator to move this to either the main Deville forums or down a few threads into the active threads section of Suspension.

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

It appears that the service ride control is a common thread for a lot of different models. I am experiencing the same information code on my 1999 eldorado ETC. What I would like to know is does this message "service ride system" seem relevant at all if the suspension, stability and safe riding conditions still exist. Is this overkill by GM to have customers who are afraid something disastrous will happen if they do not have this error message taken care of by a "professional GM qualified mechanic"? I personally think these messages play to our sense of fear. And if we do not spend up to $3000 ta make this service message disappear we will all be tossed into some other dimension, think "The twilight zone" Just sayin.

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

Originally Posted by lowandslow

im new to the discusion and site so work with me. Im in the process of disabling the service ride control message on my 94 caddi deville 4.9. I need to kow what the module looks like i found some in the trunk area but dont know which one it is or what wires to cut. If anyone has pics of the steps, can you let me know.

Re: Speed Sensitive Suspension and the "SERVICE RIDE CONTROL" message

Originally Posted by sdhow

Mike,

Mine, too, gives the IO39 error code, but the dealership said they checked the ESSC (Electronic Speed-sensing Suspension Control) module (what you refer to as a "body control module") and this is not the culprit in the case of my car. Supposedly, info on the vehicle speed, lift/dive, etc. are sent into the PCM (Powertrain Control Module, located under the right side of the dash) where this info is digested and then passed on to the ESSC to signal for suspension control changes. The accelerometer (or lateral motion switch; located under the center of the front seat, at the front of the first body cross member support) is supposed to send direct signal to the ESSC on the lateral g-forces the car is experiencing at any given moment. The dealership is telling me that the PCM is faulty and is not passing on readings to the ESSC, therefore, the ESSC cannot relay the necessary data to the struts. Believe it or not, the PCM lists for less than the ESSC! Of course, there is also the PROM plugged into the PCM, which has been linked to PO39 error code (TCC/VCC engagement problem), but I don't think these two are related.

PCM
GM Part # 88961139

ESSC
GM Part # 22154531

Does any of this make sense??? Drop me an email at sdhoward@parker.com and we can discuss in more detail.

Thanks for the reply!

Sean Howard

On my 93 Eldo with the optional Touring suspension (which has the same CVRSS as your car) it has 4 sensors instead of just the one under the seat. This is often overlooked as the 93-94 cars use their own special system that is not compatible with the OBDII systems that everyone is currently working on.

I"ve had many arguments with many individuals in regards to this matter, but have since found that my understanding of the system (that I am speaking of) is better than most since I am WELL versed on OBDI issues.

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Let me TOTALLY clear here. The suspension I'm speaking of is ONLY the optional 1 used on N* equipped Eldorado/Seville/Devilles for 93-94.

Its is a system that stands alone as it was ONLY used for 2 years.

That being said, it should also be noted that the suspensions for the same car with a 4.9 (and standard transverse leaf spring) are DIFFERENT!

I have been round and round with various members of this site (including moderators) and have found this to be true based on 20+ years of diagnostic/shop manager/mechanic experience.

(and months of hunting for a matching suspension/controls as the 93ETC N* w/optional touring suspension that I own)